The present invention relates to improved cleaning compositions formed of hydrogen-containing fluorochlorohydrocarbons with two to three carbon atoms in admixture with partially fluorinated alkanols with two to four carbon atoms, and to processes for cleaning surfaces of objects using such compositions.
Very high demands are made on solvents used for cleaning purposes. Such solvents should have a relatively low boiling point and be non-flammable and largely non-toxic and also have a high solvent power for the impurities which are to be removed. However, these demands cannot as a rule be met by only one single pure solvent. Therefore in practice a large number of solvent mixtures having compositions which differ to a greater or lesser extent are used. It is therefore generally known also to use mixtures of fluorochlorohydrocarbons (as the principal solvent) with a co-solvent in addition to pure chlorinated and/or fluorinated hydrocarbons for industrial cleaning processes or for vapor degreasing. Such mixtures may be either non-azeotropic or azeotropic or azeotrope-like. As used herein the term "azeotrope-like" refers to mixtures which boil at a substantially constant temperature across a relatively large concentration range (change in boiling temperature of not more than 5.degree. C.) and which therefore behave similarly to azeotropes in practical use.
Although many attempts have already been made to produce cleaning compositions with the desired properties for different fields of use, the known mixtures are still in need of improvement in their use properties, toxicological properties and properties affecting the environment. For instance, technical advances in the field of fluxes have resulted in new requirements relating to the ability to remove these newly developed fluxes. These requirements are not always or frequently only unsatisfactorily met by the known solvent mixtures. Or other known solvents are multi-component systems of complicated composition or contain relatively large proportions of solvents which present toxicological and/or safety hazards (e.g. have a low flash point). In still other solvent compositions, it is desirable to find new solvents which are equally well suited for their respective purpose to replace other solvents which adversely affect the environment. Therefore there remains a need for new solvent mixtures with special properties which also are relatively safe toxicologically and environmentally.